Battery

Abstract

An energy storage device includes an electrode assembly, a current collector, and a case accommodating the electrode assembly and the current collector, wherein the case has an inner surface provided with a recess, and a portion connecting the electrode assembly and the current collector or a portion connecting a conductive member connected to the electrode assembly and the current collector is at least partially disposed opposite to the recess.

1 . An energy storage device comprising an electrode assembly, a current collector, and a case accommodating the electrode assembly and the current collector,
 wherein the case has an inner surface provided with a recess, and   a portion connecting the electrode assembly and the current collector or a portion connecting a conductive member connected to the electrode assembly and the current collector is at least partially disposed opposite to the recess.   
     
     
         2 . The energy storage device according to  claim 1 , wherein the current collector is in direct contact with an inner surface of the recess, or is in indirect contact with the inner surface of the recess via a member different from the current collector and the case. 
     
     
         3 . The energy storage device according to  claim 1 , wherein the current collector has a connection portion connected to the electrode assembly or a connection portion connected to the conductive member, and a fastened portion fastened to the case,
 the connection portion is disposed opposite to the recess, and   the fastened portion is disposed opposite to the portion other than the recess of the case.   
     
     
         4 . The energy storage device according to  claim 3 , wherein the current collector is formed into a stepped shape such that the connection portion is disposed inside the recess relative to the fastened portion. 
     
     
         5 . The energy storage device according to  claim 1 , wherein the recess corresponds to a thin portion of the case. 
     
     
         6 . The energy storage device according to  claim 5 , wherein the thin portion is provided with a projection. 
     
     
         7 . The energy storage device according to  claim 1 , wherein the electrode assembly includes a main body portion and a tab projecting from the main body portion, and
 the tab is connected to the current collector or the conductive member.   
     
     
         8 . The energy storage device according to  claim 7 , wherein the electrode assembly includes electrodes that are wound to be layered,
 the tab is disposed in one of two portions of the electrode assembly divided by a plane that is perpendicular to a layered direction of the electrodes and includes a winding axis of the electrode assembly, and   the recess is provided at the inner surface of the case toward which the tab projects.